Several Problems Should Be Paid Attention to in Chemical Engineering Principle Teaching

Several Problems in the Teaching of Chemical Engineering Principles Xu Linmei (College of Chemical Engineering and Materials Engineering, Jiangnan University, Wuxi, Jiangsu 214036) Teaching methods are organically integrated into the teaching practice, aiming at improving the teaching effect of the Chemical Engineering Principles course to cultivate scientific research and practicality. Combining pioneering talents.

The principle of chemical engineering is a technical basic course, and it is also a degree course for many engineering colleges. However, its content involves many disciplines, and it is highly cross-cut and difficult to teach. Therefore, teaching methods to improve chemical engineering principles are particularly important. Teaching is not only the process of imparting knowledge, but also the process of information exchange. Through lectures and discussions, students should not only learn basic theoretical knowledge, but also understand scientific research ideas, methods, frontier developments in scientific development, and latest scientific research results, and constantly generate new ideas and sparks in the process of information exchange. Thinking and research enthusiasm to cultivate talents with practical and scientific research talents. Therefore, in order to truly achieve the purpose of cultivating practical and research-oriented talents, this article will discuss how to teach chemical engineering courses.

First, pay attention to methodological teaching, and cultivate scientific research thinking. The ancient saying goes: “To teach people to fish is only for the needs of a meal, to teach people to fish, and to use them for life.” Developing students’ scientific thinking is one of the important tasks of higher education, and scientific research Thinking is the basic quality necessary for innovative talents. Methodological teaching is an important means of cultivating students' scientific thinking. It integrates the thinking, principles, methods, professional status, progress, existing problems, and future research directions of science research into teaching. The principle of chemical engineering is a major course that mainly studies the operation principle of each unit, the structure of typical equipment, and the calculation of equipment process dimensions. However, students are generally afraid of the course. As teachers should carefully study materials, based on full access to relevant information, to understand the relevant disciplines, meticulous processing of teaching materials, repeated review of the teaching content, reasonable arrangements, so that the details are appropriate, focused. Simplify, concretize, and clarify the complicated contents that students cannot easily master. How to use the method to derive the formula and draw conclusions, discuss what issues, so that students can quickly understand the content of the explanation to obtain knowledge, how to inspire and guide students to creative thinking and so on. Efforts are being made to broaden teaching information, add cutting-edge knowledge in disciplines, and development history of related disciplines and disciplines, enrich the latest scientific research results in teaching, and increase the attractiveness of teaching content to students because the best motivation for learning is to learn The content itself is of interest.

When explaining a unit operation, the development history, current status, progress, existing problems, and future research directions of the unit operation may be introduced first to cultivate students' scientific thinking ability. For example, when explaining the “Liquid-Liquid Extraction” unit operation, we first introduced that the working people of our country were the first to use organic solvents (soju) to extract drugs or the active ingredients in fragrant flowers from the world as the founder of wine or flavor (at least Thousand years of history). The Nemst distribution law at the beginning of the 19th century laid the foundation for the theory of extractive chemistry. In the mid-19th century, Peligot first discovered that ether can extract uranyl nitrate from nitric acid solution in the field of inorganic chemistry, and the study of chemical technology of nuclear fuel promoted the 1940s. Later extraction of large-scale applications in the industrial field. Because at that time, the nuclear fuel separation process was characterized by the separation of a product with high purity requirements from a large number of impurities, people began to use a method of repeated precipitation and fractional crystallization, which not only consumed a large amount of chemicals (such as refining a kilogram of pure uranium It is necessary to consume tons of chemicals, but also produce a large amount of radioactive waste that is difficult to handle, and the purity of the resulting product cannot meet the requirements. Inspired by Peligot's extraction method, people succeeded in obtaining industrial applications by extracting uranium with tributyl phosphate in 1945. The extraction of this technology followed by rapid development. Supercritical fluid extraction, reverse micelle extraction, aqueous two-phase extraction and microwave extraction have emerged. This enables students to understand the history, current status, and development of extraction, and the rise of learning is stimulated. At the same time, the problems of various methods can be pointed out, such as the high cost of supercritical fluid extraction and high equipment safety requirements. Reverse micelle extraction is still in the laboratory research stage, and it is necessary to overcome the problem of surfactant contamination of products. To enable students to understand the development of science and technology, Xu Linmei: The frontiers and trends of several issues that should be emphasized in the teaching of chemical engineering principles. Then explain the basic concepts of liquid-liquid extraction, calculation, equipment used, and status in the separation project. Let students learn “Liquid-Liquid Extraction” from the perspective of the history of scientific development and the status quo of the discipline

The chapter has cultivated students' scientific thinking, clarified the purpose and significance of learning, and improved teaching effectiveness.

Second, pay attention to heuristic teaching, mobilize the potential of learning Heuristic is the active classroom atmosphere and fully mobilize the students' enthusiasm for learning pedagogy. It creates a situation, a fresh and active classroom atmosphere to induce students to think independently, stimulate their desire for knowledge, and mobilize their subjective initiative. Instead of simply letting students know something, remember a conclusion. Heuristic teaching can use flexible teaching methods. Suspense-style heuristic teaching: In teaching, teachers can set difficult questions, such as explaining "distillation"

The essence of the principle in the first chapter, because students have learned from the physical chemistry course that “through multiple partial vaporizations and multiple partial condensations, high-purity volatile products and involatile products can be obtained respectively”, so when explaining First of all, this process is briefly explained with a phase diagram, followed by analysis, resulting in the conclusion that "theoretically feasible and difficult to achieve on the project", and then put forward some of the problems of vaporization and partial condensation in the implementation of the project, natural guidance The student associates with the need for a lot of heat exchangers (intermediate heaters and intermediate condensers), the result is a complex equipment, high equipment costs; in addition to several partial vaporization and multiple partial condensation produces many middle distillates (visible from the phase diagram ), resulting in low material utilization, and the final product yield is very small. Therefore, the product cost is too high, so it is not feasible in engineering. How to solve these problems and how to solve these problems, from the shallow to the deep, explain the profound things in simple language, trigger students to think and explore, make the students' ideology active, and get a solution to the problems in thinking and exploring. Inferential heuristic teaching: The conclusions or formulas of certain problems are easily deduced through logical reasoning. If you are deciphering the formula, you must clarify the premise, basis, and method of derivation. Help students understand the formula's derivation process, understand its application scope, and formulas are easy to remember on the basis of understanding. When there are many chapter formulas, find rules to let students master memory skills without having to memorize them. If there are many formulas in the “Absorption” chapter (many absorption rate equations), students will find it difficult to remember and teachers may seek out the common points of law and publicity to help students remember. Summarizing and summarizing the heuristic teaching: After learning certain content, such as a chapter, it should be summed up in a timely manner so that students can feel clear and have an overall impression.

Third, pay attention to practical teaching, to stimulate learning enthusiasm The chemical engineering principle is also a highly applied curriculum, should answer the questions raised in the application of engineering through the study of the relevant processes. According to the technical and economic characteristics of each unit operation, the selection of 'process and equipment' is carried out to meet the characteristics of the designated system and to meet the requirements of the process economically and effectively. For the separation of homogeneous mixtures, there are A wide variety of unit operations are available for selection, each unit operation has its strengths and weaknesses, and the key is to select the appropriate separation unit operation to make it technically feasible and economically reasonable, such as the separation of ether and acetone, due to their All of them are nonionic organic compounds, so they cannot be separated by ion exchange, magnetic separation and electrodialysis.

At the same time, the surface properties of the two are very different, and foam separation and bubble separation cannot be adopted either. As a result, it is possible to select from among distillation, absorption, extraction and other operations that are reasonably separated. However, in the end what kind of separation operation is adopted, economic rationality must also be considered. In addition, if “distillation” is used to separate the homogeneous mixture, selecting the appropriate operating pressure is closely related to the economics of the separation process. For example, the selected operating pressure cannot make the temperature of the overhead vapor (temperature related to the operating pressure) lower than 40°. C, because the top condenser is best to use cooling water or air as the cooling medium, otherwise the cooling medium needs to use the refrigerant, which is very uneconomical; the boiling temperature of the tower kettle liquid should not be too high, because the temperature of the kettle liquid is usually increased. With steam heating, the boiling temperature of the tower kettle liquid is high, and the requirement for the boiler is increased. Generally, the saturation temperature of the heating steam does not exceed 180*C. Otherwise, it is uneconomical. Usually the project will also encounter the following questions: how to carry out the calculation of the process and equipment design, in the absence of data, how to organize experiments to obtain the necessary design data; how to operate and adjust to meet the different requirements of production in How to find the cause of the malfunction when the operation fails. When explaining, you should use engineering examples as much as possible to use the learned knowledge to analyze problems and solve problems so as to cultivate and improve the actual working ability in scientific research and production practice.

In short, through practical teaching, students can really realize the importance and necessity of this course, so as to stimulate students' learning enthusiasm and consciousness.

Fourth, pay attention to interactive teaching, and enhance the teaching effect of teaching effects, is related to many factors, but teaching interaction is very important, that is, teachers and students in the process of teaching and learning, teachers understand the teaching effect, master the teaching initiative, students tight With teachers' ideas, they have a lot of interest and good results. The teaching interaction should focus on the students' original foundation, psychological characteristics, classroom effects and after-school reflections. Because teaching is a two-way behavior, the main body of teaching is students, and successful classroom teaching should integrate student participation, student's subjectivity and student's development. Before preparing lessons, students should fully understand the original foundations of the students, such as the previous courses, learning conditions, and professional characteristics. According to the original foundation of the students, they can prepare lessons and teach students in accordance with their aptitudes so as to mobilize the enthusiasm and initiative of students' learning to their full potential. Should pay attention to the psychological characteristics of the students, teachers should maintain an equality with the students, (turned to page 91) Journal of Wuxi Institute of Education During the Skimming process, students should read the title of the article and the subject sentence of each paragraph. Quickly browse the full text to obtain an overall image of the article's content, structure, and author's writing intent.

Then there is Scanning. Jump reading is a symbol recognition process for obtaining specific information. The skipping of an article generally starts around questions, such as choosing correct answers to reading comprehension questions and answering specific questions. Therefore, teachers should design several task-type problems in advance, so that students can quickly find the scope of the questions in the text with the questions (Questionareas), in order to improve the reading speed, and experience the joy of a smooth solution to the problem.

The subject of the text, the structure of the article, and the meaning of each paragraph.

Reading activities in these three links should be limited in time. Teachers can ask students different reading speeds according to different reading methods and tasks.

This stage is mainly used to help students consolidate and express reading content. Usually students can discuss, express their opinions, make suggestions or solve problems, evaluate the characters in the text or imagine the multiple endings of the story.

Task-based teaching provides operable conditions for evaluating students in multiple levels, from multiple perspectives and in multiple forms. Whether the student completes the task in quality and quantity in reading, the teacher can evaluate the completion time, the task content, the deployment form and the display requirement. At the same time, students can also make procedural evaluations of their written work, verbal responses, classroom presentations, learning attitudes, participation, and spirit of cooperation. This will enable students to be motivated, generate self-confidence and sense of accomplishment, and translate into motivation for progress.

Fourth, expand students’ knowledge to allow students to read articles in various genres and genres. They should be given access to articles on history, geography, humanities, tourism, popular science, and biographies. In particular, the culture, customs, and culture of English-speaking countries The article, at the same time, should pay attention to cultivating students' awareness and sensitivity to cultural differences. This will enable students to improve their reading interests, deepen reading comprehension, and develop reading habits.

In short, in reading teaching, as long as we always follow the principle of interest, take students as the principle principle and the principle of teaching students in accordance with their aptitudes; make ingenuity, explain the essence, guide the method, practice in place, and guide students to insist on reading in a big way and read the details carefully. If you read and read doubts again, you will be able to cultivate high-quality reading talents with four readings.

Chen Hao. Subject's participation in the process of teaching English reading. Foreign Language Teaching in Primary and Secondary Schools, 2002, (24).

(Continued from page 86) Harmony and democracy, respecting students, treating each other sincerely, strengthening communication, minimizing the distance between teachers and students, and adding a sense of intimacy; encouraging and affirming students, promoting student quality problems, unconventional innovations, Students are allowed to publish different opinions and create a relaxed and harmonious atmosphere of free communication. In the classroom, the teacher should pay attention to the student's expression at any time. If the student is awkward, it means that the student does not understand the content of the explanation and needs to explain it in detail or explain it from another angle or in another way until the student understands it. When explaining chapters that are more abstract or boring, according to the students' attention in class, they can give some interesting project examples in a timely manner to activate the classroom atmosphere and stimulate learning interest. Information feedback after class can't be ignored, but the common problem is that students actively communicate with teachers very little. For this reason, students should actively communicate with students after class to understand the effect of lectures, learning difficulties, and even life. Situation, timely adjustment of teaching progress and methods of improving teaching methods. Focus on the interaction between teaching and learning, teachers and students through the organic combination of teaching process, to achieve the "teaching" and "learning" the best combination of strong teaching results.